46 On the Affinities of CeratophyUac&t. 



a bud) enveloped by the persistent membrane of the nucule. 

 The point.- of difference, such us the want of petals, the 

 nearly sessile anthers, and the single ovary of'Ceratophyllum, 

 are sufficiently obvious : but they cannot be thought to weaken 

 materially such peculiar and strongly marked affinities. The 

 lower degree of developement, both of the organs of vegetation 

 and fructification of Ceratophvllum, are, perhaps, chiefly attri- 

 butable to the entirely submersed habit of the genus. 



It a comparison be next instituted between Ceratophyllum 

 and the order Cabombacese or Hydropeltidea?, affinities will be 

 perceived, the existence of which have been, I believe, hitherto 

 unsuspected. This order, first indicated by Richard,* and 

 considered by De Candolle as a tribe of Podophyllea?, has 

 been referred to Nymphnsaceae both by Brownt and Lindley '-\ 

 it is, however, a distinct order, more closely allied to Nelum- 

 biaceae than Nymphaeaceas, as will be shown in the course of 

 these remarks. It includes tun genera, both peculiar to the 

 American continent, via. Drascnin,^ the only species of which 

 (/»'. peltata of Pursh) abounds in ponds and slow-flowing 

 Streams from Canada to Florida; and Cabomba of Aublet, 

 which comprises two species hitherto confounded, || the one a 



• Ann. <lu Museum, 17, j>. 230. 



I Appendix to Capt. King's Voyage to New Holland. 



Bd. 2, /<• 13. 



§ Schreber, Hour,: Plantarum (1798), p. '372. — Hydropeltis, Michx. 

 Jl. (1803) 1. }>■ 324. This genua bavingbeec characterised and described 

 by Schreber Ion- before th< Plots "i" ftfichaux was published, I see no 

 ■ in for adopting tli' 1 name imposed by the Latter, as is done by most 

 European botanists. 

 ii 1 subjoin ili«- characters and svnomony of the two species. 

 1. Cabomba aq,i ltica; foliis natantibus orbicularis ; floribus luteis; 

 mperl) 2. — C. aquarica, Aubl. /</. Qvian. l, _p. 321, t. 

 l-.-i | Richard, nun. museum, 17, p. 830, t. 6,jig. 88; D C. lytt, 2, 

 /■ '. iuii. t. absque man. (opt. ; Rossi. \ Sehull. sysl. 

 II \m. In stacnit et rivulis CayenntS, Auhlrt ; in Suri- 

 nam, Dr. Herring. 



